We know the human tongue is extremely sensitive. Go ahead: touch something with your tongue. There isn't a naked surface on your body that's better equipped for sheer sensation. There's nothing more plastic, built to adapt and optimize itself for new experiences. Not only is your tongue fully equipped with a sense-optimized surface, but anything you experience on your tongue gets mainlined directly into your brain. So if we're serious about hacking the body to provide new kinds of sense experiences, forget about the fingertips. Forget anything on the outside of the skull. The answer is obvious: trick out your tongue.
The Tongueduino is the brainchild of MIT Media Lab's Gershon Dublon. It's a three by three electrode pad that rests on your tongue, runs through an Arduino controller, and connects to one of several environmental sensors. Each sensor might register electromagnetic fields, visual data, sound, ambient movement — anything that can be converted into an electronic signal. In principle, this could allow blind or deaf users to "see" or "hear" with their tongues, or augment the body with extrahuman senses.
Dublon, an electric engineer by training, studies how "sensor networks might become extensions of our nervous systems — networks of remote, distributed sensing prosthetics." He has been experimenting with his Tongueduino himself for the past year and is now beginning training with a group of twelve volunteers. "Through Tongueduino, we hope to bring electro-tactile sensory substitution beyond the discourse of vision replacement, towards open-ended sensory augmentation that anyone can access," he writes.